This invention relates to a class of polycyclic, fused ring compounds, metal complexes formed therefrom, and to polymerization catalysts derived from such complexes that are particularly suitable for use in a polymerization process for preparing homopolymers and copolymers of olefins or diolefins, including copolymers comprising two or more olefins or diolefins such as copolymers comprising a monovinyl aromatic monomer and ethylene.
Constrained geometry metal complexes and methods for their preparation are disclosed in U.S. Pat. No. 5,703,187. This publication also teaches the preparation of certain novel copolymers of ethylene and a hindered vinyl monomer, including monovinyl aromatic monomers, having a pseudo-random incorporation of the hindered vinyl monomer therein. Additional teachings of constrained geometry catalysts may be found in U.S. Pat. Nos. 5,321,106, 5,721,185, 5,374,696, 5,470,993, 5,541,349, and 5,486,632, as well as WO97/15583, and WO97/19463.
Certain highly active, polyaromatic, metal complexes, especially derivatives of cyclopentaphenanthrenyl ligand groups are disclosed in U.S. Ser. No. 09/122,958, filed Jul. 27, 1998, now U.S. Pat. No. 6,150,297 (WO99/14221, published Mar. 25, 1999). Metallocenes containing four fused rings arranged on a central 5-membered carbon ring are disclosed in WO99/02540.
Despite the advance in the art obtained by the foregoing metal complexes, catalysts possessing improved catalytic performance are still desired by the industry. Accordingly, it would be desirable if there were provided metal complexes having improved catalytic properties to the foregoing known compounds.
According to the present invention there is provided a polycyclic, fused ring compound corresponding to the formula: (Cp*)pxe2x80x94M* (I) or CpM(Z)z(X)x(L)1(Xxe2x80x2)xxe2x80x2(II),
where Cp* is a polycyclic, fused ring ligand or inertly substituted derivative thereof comprising at least: (1) a cyclopentadienyl ring, (2) a 7 membered polyatomic ring, and (3) one or more aromatic ring systems, with the proviso that said 7 membered ring (2), is fused to both the cyclopentadienyl ring (1), and said one or more aromatic ring systems (3), and substituted in at least one ring position with a substituent group resulting in sp2 hybridization on the ring atom bonded thereto, said Cp* having up to 60 atoms other than hydrogen;
p is 1 or 2;
when p is 1, M* is hydrogen, an alkali metal or an alkaline earth metal halide, and, when p is 2, M* is an alkaline earth metal; said M* being bound to at least one of the non-fused, ring-carbons of the cyclopentadienyl ring, (1);
Cp is the aromatic ligand group derived from Cp* by removal of M*;
M is a metal selected from Groups 3-10 or the Lanthanide series of the Periodic Table of the Elements;
Z is either:
a) a cyclic ligand group containing delocalized xcfx80-electrons, including a second or third, fused, polycyclic ligand, Cp, said Z being bonded to M by means of delocalized xcfx80-electrons and optionally also covalently bonded to Cp through a divalent bridging group, Zxe2x80x2, or
b) a divalent moiety of the formula xe2x80x94Zxe2x80x2Yxe2x80x94, wherein,
Zxe2x80x2 is SiR62, CR62, SiR62SiR62, CR62CR62, CR6xe2x95x90CR6, CR62SiR62, BR6, BR6Lxe2x80x3, or GeR62;
Y is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NR5xe2x80x94, xe2x80x94PR5xe2x80x94; xe2x80x94NR52, or xe2x80x94PR52;
R5, independently each occurrence, is hydrocarbyl, trihydrocarbylsilyl, or trihydrocarbylsilylhydrocarbyl, said R5 having up to 20 atoms other than hydrogen, and optionally two R5 groups or R5 together with Y form a ring system;
R6, independently each occurrence, is hydrogen, or a member selected from hydrocarbyl, hydrocarbyloxy, silyl, halogenated alkyl, halogenated aryl, xe2x80x94NR52, and combinations thereof, said R6 having up to 20 non-hydrogen atoms, and optionally, two R6 groups form a ring system;
Lxe2x80x3 is a monodentate or polydentate Lewis base optionally bonded to R6;
X is hydrogen or a monovalent anionic ligand group having up to 60 atoms not counting hydrogen;
L independently each occurrence is a neutral ligating compound having up to 20 atoms, other than hydrogen, and optionally L and X are bonded together;
Xxe2x80x2 is a divalent anionic ligand group having up to 60 atoms other than hydrogen;
z is 0, 1 or 2;
x is 0, 1, 2, or 3;
t is a number from 0 to 2, and
xxe2x80x2 is 0 or 1.
The above compounds may exist as isolated crystals, as a mixture with other compounds, in the form of a solvated adduct, dissolved in a solvent, especially an organic liquid solvent, in the form of a dimer, or as a chelated derivative, especially wherein the chelating agent is an organic material such as ethylenediaminetetraacetic acid (EDTA).
Also, according to the present invention, there is provided a catalyst for olefin polymerization comprising:
A. i) a metal compound of formula (II), and
ii) an activating cocatalyst,
the molar ratio of i) to ii) being from 1:10,000 to 100:1, or
B. the reaction product formed by converting a metal compound of formula (II) to an active catalyst by use of an activating technique.
Further according to the present invention there is provided a process for the polymerization of olefins comprising contacting one or more C2-20 olefins, including cyclic olefins, under polymerization conditions with a catalyst comprising:
A. i) a metal compound of formula (II), and
ii) an activating cocatalyst,
the molar ratio of i) to ii) being from 1:10,000 to 100:1, or
B. the reaction product formed by converting a metal compound of formula (II) to an active catalyst by use of an activating technique.
The present catalysts and polymerization processes are especially efficient for production of olefin homopolymers, copolymers of two or more olefins, in particular, copolymers of ethylene and a vinylaromatic monomer, such as styrene, and interpolymers of three or more polymerizable monomers over a wide range of polymerization conditions, and especially at elevated temperatures. They are especially useful for the formation of ethylene homopolymers, copolymers of ethylene and one or more higher xcex1-olefins (that is, olefins having 3 or more carbon atoms), copolymers of ethylene, propylene and a diene (EPDM copolymers), copolymers of ethylene and vinylaromatic monomers such as styrene (ES polymers), copolymers of ethylene, styrene, and a diene (ESDM polymers), and copolymers of ethylene, propylene and styrene (EPS polymers). Examples of suitable diene monomers include ethylidenenorbornene, 1,4-hexadiene or similar conjugated or nonconjugated dienes. Surprisingly, the metal complexes of formula (II) demonstrate equivalent or improved catalytic properties compared to metal complexes containing polycyclic, fully aromatic, hydrocarbon ligands, and they and their degradation products are more biologically inert compared to compounds containing fused, polycyclic, fully aromatic hydrocarbon ligands.
The catalysts of this invention may also be supported on a solid material and used in olefin polymerization processes in a slurry or in the gas phase. The catalyst may be prepolymerized with one or more olefin monomers in situ in a polymerization reactor or in a separate process with intermediate recovery of the prepolymerized catalyst prior to the primary polymerization process.
The compounds of formula (I) are useful in the formation of the compounds of formula (II) as well as in the preparation of other metal complexes. In addition to their use as polymerization catalysts, compounds according to the present invention may be used for hydroformulation, hydrogenation or oligomerization processes.